The subject matter of the present invention is a process for the preparation of ketoximosilanes and ketoximoalkoxysilanes. These silicon compounds are suitable especially as crosslinking silicon compounds in the production of compositions which can be hardened by exposure to moisture at room temperature to form elastomers, and which can be stored with the exclusion of water. Such compositions are obtained by mixing crosslinking compounds and diorganopolysiloxanes having condensable terminal groups.
It is known to prepare ketoximosilanes by the reaction of alkyl trichlorosilanes with ketoximes (cf. DE-PS No. 13 01 140, EP-A2-0 082 324, SU Pat. Nos. 435,243 and 724,514). In the performance of this process there is always the danger that ketoxime or ketoximosilanes will come in contact with substances of an acid nature. The intermediate formation of HCl will then form the hydrochloride of the ketoxime. For example, methylethylketoxime boils at standard pressure at 152.degree. C., while its chloride decomposes very violently at a temperature as low as 50.degree. to 70.degree. C. Such decompositions can also be triggered by catalytic amounts of, e.g., ferric chloride. Ketoximosilanes under such conditions have a tendency to decompose exploxively. L. J. Tyler (Chem. Eng. News 52 (1974) 35, 3) reports on two violent explosions of this kind.
The problem therefore existed of finding a process for the preparation of ketoximosilanes in which the danger of decomposition or explosion does not exist.